Preparation of d-tartaric acid



Patented Apr. 16, 1940 1 UNITED STATES PATENT 'ossji'cs,

PREPARATIN ;m'-PARIC Richard Pastcrnack, Brooklyn,

Brown, Jamaica, N, Y., assignors and Ellis Y. to Charles Pfizer 8; Company, Brooklyn, 8.1., a corporation oi. New Jersey No Drawing.

pplicati on 13, 1938;.

Serial lilo. 245,420

3 Claims. (01. 26H) This invention relates to the preparation of d-tartaric acid and has for its object to provide an improved, economical process for this purpose. Many attempts have been made to prepare d-tartaric acid by'the oxidation of carbohydrate materiaL- All of the published processes produce a mixture of isomers and Icy-products from which' separation of the d-tartaric acid is conmiercially impracticable. i0

Ellis, in U. SI Patent 789,269 (1905), describes anodic oxidation of saccharine matters (citing grape sugar as an example) to produce a mixture of organic acids including tartaric acid. The Diamalt A. G'. of .Munich, German s; b 15. ginning in 1918 patented'processes for preparing tartaric acid from saccharic acid or from glucose,

oxidized by an electric current or by peroxides in the presence of organic catalysts. Odell in U. S.

Patent 1,425,60

(1922') discloses thenitric acid 0 oxidation of a carbohydrate -or, saccharid in the presence of metalliferous catalysers to produce a'solution containing oxalic acid, tartarir acid, saccharic acids."

acid, and perhapS-otherpr'ganic Milas and Terry (J. Am. Chem. Soc. 4'; :;141 2-,s, 1925) have described the oxidation of tumaric to racemic tartaric acidby means of potassium chlorate in the resence of an osmium oxide catalyst, Zemplen U. S. Patent 1,605,419); Homer- 0 ling (U. S. Patent 1,834,057) and Stokes '(U. S. Patent 1,870,472) describe. other methods ofoxie dizing rumanc acid, starch, etc.-, to racemic tartaric acid. None of these processes, in so far as we have been able to determine, has been com mercially successful, apparently because of the difficulty of separating'theisome'rs and the lack or any substantial market for the isomers of dtartaric acid.

W. E. Barch However, we have now found that-on account of 5b the favorable structure of 5 -keto-,d-gluconic acid,

(J. Am.

apparently had no conception of of obtainingd-tartaric acid free Barch obtained only a mixture of primarily consisting of itrihydroxy and. the tartaric-isomers. Such a a practical source of d-tartaric it is possible by a suitable selection of oxidizing agentto'prepare from it d-tartaricacid substantially free from isomers worthless or S-keto-d-gluconic acid obtainwhich are as calcium. salt of dimcult to remove. The

Y fi-keto -gluconic acid was suflicient excess of removed with barium carbonate.

"about 4 hours.

Chem. sec. 55:3653 -3658, 1933) describes the: oxidation .of 5-keto-d-gluconic acid'with nitric acidin the presence of passed through at 50.

and with no lay-products able by biologicalmethods [Bout-roux (com s. rend. 127:1224). Bernhauer (Biochemische Zeitsch'rift 280:367-72'), and {Kluyver (Rec. trav.

Formation of d-tartaric acidifree ofisomers may take place either: under acid orunder alkar- I,

line conditions, using oxygen-containing gases with or "without catalysts. "The temperature is 0 :not critical, exceptthat as the S-ketoacid is con siderably decomposed at temperatures .above 80 C. we-prefer to work at more moderate tempera-- ,For the following examples a solution oi free prepared by treating any of the calcium salt witha sulphuric acid to' decompose it completely. Theresulting" acid solution can-be used directly or the excess sulphuric acid can be=z0 aqueous suspension Example. 1.-Potassiuin 5-keto gluconateis produced by treating 90 :grams potassiumcar' l.

'bonate in 2% liters twice :normal h y-- I calcium fi keto -nsd d gluconate trihydrate. At 40 C. a finely disdroxide solution with 334 grams persed stream ofjoxygen-is passed thru the mixture. The reaction complete whenthe test with Fehling"s solution isnegative.. takes The calciumcarbonate is removed by filtration and the illtrate adiustedto pH 3.5 with-acetic acid. -A crude acid potassium tartrate containing some acidpotassium oxalate precipitates and is s'eparated'by flltration'. ilt can-be purified-by 35 any of theknown methods,-for instance by tractional recrystallization from water.

Example 2.'-'This process is the same as that of Example 1 except that 10' grams of vanadium pentoxide are added and the Example 3.-'An aqueous s'olutioncontaining Y 300 grams of b-keto-d-gluconiciacidis diluted'to a volume of two liters. To this-is added 10;gra ,ms vanadium pentoxide, and finely dispersedoxygen After about eight hours the reaction is practically. complete. Thetartaric I acid {is recoveredin theform Qi potaSsium. acid .60 tartrate as in the previous examples.

Example 4. .-An aqueous solution of 208 of 5--keto'-d-gluconic .-ac id isftreated with four. moles of nitric acid and 10 8131 801 manganese dioxide; The mixture is diluted to a v olumeot 66 temperature is held between and-70 C. during the oxidation which takes about four. hours. Contamination with ox-:

alate is even less than. inExample 1.

two liters and finely dispersed oxygen is passed through for seven hours while the whole is maintained at a temperature of 70f C. The solution is brought to a pH of 3.5 with potassium carbonate to precipitate acid potassium tartrate, which in this case is substantially free from oxalate. Under the conditions of this experiment cobalt, vanadium and titanium give equally good yields, .while molybdenum, chromium, iron, cerium, nickel, uranium and tungsten all catalyre the action but do not act as efl'iciently as manganese. I'he nitric acid is present only for the purpose of adjusting the pH. Under the conditions given it does not contribute to the oxidation in any substantial degree.

The invention claimed is:

1. Process for producing d-tartarlc acid which comprises oxidizing a member selected from the group consisting of 5-keto-d-gluconic acid and its salts by the action of an omen-containing gas at a pH between 0.1 and 14.

2. Process for producing d-tartaric acid which comprises oxidizing a member selected from the group consisting of S-keto-d-gluconic acid 3. Process for producing d tartaric acid which comprises oxidizing a member selected from the group consisting or 5-keto-d-gluconic acid and its salts by means of a flnelyidispersed oxygen-containing gas in the presence of manganese as a catalyst.

RICHARD PAB'I'ERNACK. ELLIS V. BROWN. 

